import java.util.ArrayList;
import java.util.Collection;

public class Test1 {
    public static void main(String[] args) {
            Collection c1=new ArrayList();
            Collection c2=new ArrayList();

            c1.add("奔驰");
            c1.add("奥迪");
            c1.add("宝马");
            c1.add("大众");

            c2.addAll(c1);
            System.out.println(c1);
            System.out.println(c2);

            System.out.println("容器1中汽车品牌的数量为："+c1.size());
            System.out.println(c1.contains("奥迪"));

            c1.retainAll(c2);
            System.out.println(c1);

            c2.clear();
            System.out.println(c2);

            System.out.println(c2.isEmpty());
    }
}
